The problem inherent with any digital image (or digital video) system is the large amount of bandwidth required for transmission or storage. This has driven the research area of image compression to develop more compl...
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Pyramid image coding is a natural coding scheme for applications where progressive transmission is desired. In this kind of coder, versions of the original image at several resolution levels are formed by successive f...
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The transmission of digitized images over limited bandwidth channels motivates the use of data compression techniques. Many data compression techniques are not suitable for such applications because compression ratios...
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The transmission of digitized images over limited bandwidth channels motivates the use of data compression techniques. Many data compression techniques are not suitable for such applications because compression ratios of more than 20:1 are often required. One technique that can provide this level of compression is vector quantization. The processes of codebook generation and, especially, encoding and decoding are tasks well suited for execution on a massively parallel machine. For codebook generation, an SIMD algorithm is developed whose control flow is based on sequencing through the training data, rather than the tree structure, to achieve improved performance. Results from execution on the 16384 processor MasPar MP-1 SIMD machine are presented. The approaches taken could be adapted for other SIMD as well as MIMD machines.
This paper decribes a novel method for detecting nonstationary signals in colored noise. A first order complex autoregressive, or AR(1), signal model is used which restricts the application of the detector to low orde...
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As the complexity of a detection algorithm increases, analytic performance evaluation becomes increasingly difficult and is often intractable. In such casts, Monte Carlo simulations can be used, but they often require...
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Perfect reconstruction (PR) time-varying analysis-synthesis filter banks are those in which the filters are allowed to change from one set of PR filter banks to another as the input signal is being processed. Such sys...
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Trade-offs between the SIMD and MIMD models of architecture for parallelism are presented. Mixed-mode parallelism, where a machine can switch between the SIMD and MIMD modes of parallelism at instruction-level granula...
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Trade-offs between the SIMD and MIMD models of architecture for parallelism are presented. Mixed-mode parallelism, where a machine can switch between the SIMD and MIMD modes of parallelism at instruction-level granularity with generally negligible overhead, is discussed. Advantages and disadvantages of mixed-mode parallelism and an example of a mixed-mode parallel algorithm are given. The relationship of mixed-mode processing to high-performance heterogeneous computing is overviewed. Difficulties involved with evaluating interconnection networks for parallel machines are then considered. There are a myriad of metrics that have been used in the literature. The problems involved with choosing the most appropriate metric or weighted set of metrics, and performing "fair" comparisons, are explored.< >
The problem of minimizing the execution time of programs within a heterogeneous environment is considered. Different computational characteristics within a parallel algorithm may make switching execution from one mach...
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In motion rate control applications, it is faster and easier to solve the equations involved if the singular value decomposition (SVD) of the Jacobian matrix is first determined. A parallel SVD algorithm with minimum ...
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In motion rate control applications, it is faster and easier to solve the equations involved if the singular value decomposition (SVD) of the Jacobian matrix is first determined. A parallel SVD algorithm with minimum execution time is desired. One approach using Givens rotations lends itself to parallelization, reduces the iterative nature of the algorithm, and efficiently handles rectangular matrices. This research focuses on the minimization of the SVD execution time when using this approach. Specific issues addressed include considerations of data mapping, effects of the number of processors used on execution time, impacts of the interconnection network on performance, and trade-offs between modes of parallelism. Results are verified by experimental data collected on the PASM parallel machine prototype.< >
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